The effect of aerobic exercise with garlic and stevia supplementation on hormonal and histological changes in thyroid tissue of obese rats fed a high-fat diet

Childhood obesity has worldwide increasing and has numerous effects on other body tissues, including the thyroid. Therefore, the present study investigated the effect of aerobic exercise with garlic and stevia supplementation on hormonal and histological changes in thyroid tissue in obese rats fed with high-fat diet.

Thirty five Wistar rats were randomly divided into seven groups of healthy control: obesity induction, obesity induction+garlic, obesity induction+stevia, obesity induction+aerobic exercise, obesity induction+garlic+aerobic exercise, and obesity induction+stevia+aerobic exercise. Aerobic exercises including 40 minutes training were performed eight to 15 m/min and five days per week, for eight weeks. Garlic and stevia extracts with a concentration of 250 mg/kg were added to the daily water intake.  For structural studies the thyroid tissue and five cc of blood was transportd to the lab. for measuring the serum levels of thyroid stimulating hormone (TSH), triiodothyronine (T3) and thyroxine (T4). . For statistical analysis the one-way analysis of variance and LSD post hoc tests were used at the significant level of p<0.05.

Twelve weeks of high-fat diet in rats did not change the serum levels of TSH and T3 compared to the healthy control group (p<0.05). On the other hand, serum T4 levels of obese rats significantly increased compared to healthy controls (p<0.05). Histological analysis, on the other hand, showed that obesity causes moderate to severe structural changes in thyroid tissue; but garlic supplementation, stevia and aerobic exercise, and a combination of garlic-stevia extract and aerobic exercise slightly reduce the effects of obesity.

Induction of high-fat diet causes significant structural changes in the follicular, par follicular and colloidal sections of male Wistar rats; but the combination of aerobic exercise and garlic and stevia supplementation is mildly helpful in improving these side effects.Keywords: Aerobic exercise, Stevia, Garlic, Obesity, Thyroid hormones.